President of Friends of Forrestdale David James said during summer off-road |vehicles tore across the lake when it was dry and caused a lot of damage to the environmentally sensitive area.
�It�s been an ongoing issue for years,� he said.
�We have birds that nest on the lake when it is dry and tortoises that estivate (slow their activity during hot, dry weather) in the mud � the vehicles upset everything.�
Friends of Forrestdale help to preserve the lake, which is a nationally recognised and protected wetland, by undertaking weed eradication, bush regeneration, bird surveys, water depth analysis and rubbish removal.
It is considered a significant breeding site for black swans and an internationally important area for migratory wading birds.
Mr James said that in the past decade Forrestdale Lake�s natural environment had been disturbed by land development and long, hot summers, which caused it to remain drier for longer.
But, in recent years the unlawful use of off-road vehicles had become one of the major problems. �We applied for a $17,000 Natural Resource Management grant to complete the fence at the north end of the lake at Skeet Park, between Weld and Moore Streets,� Mr James said.
Funding will also include signage explaining the purpose of the fence to protect the natural values at the lake and information about educational walks about the natural history of the lake.
The fence is expected to be completed by the end of the year.
Anyone who sees off-road vehicles at the lake should call Armadale Police on |9399 0222 or the City of Armadale rangers.